Referring to FIG. 1, a floor edger is an electrically powered, handheld, rotary floor sanding tool. It has a motor housing which houses an electric motor and fan. A pair of handholds are attached on opposing sides of motor housing. A power cord and dust bag are likewise attached to the motor housing at other than the front side.
Referring to prior art FIGS. 1 and 2, the bell housing is a circular metal skirt firmly attached to the lower end of the motor housing, enclosing rotor head to which is attached a disk casing and a sanding pad or disk. The sanding disk and casing protrude very slightly below and out in front of the bell housing along the front edge to enable contact of the disk with the floor and use of the edger up close to baseboards and other obstructions on the floor. Rotation of the sanding disc from the top view is clockwise. The bell housing forms a skirt-like enclosure around the disc casing and a plenum over it, to which suction is applied by an internal suction fan for removing the dust generating by the abrading of the floor materials during sanding operations. The dust is pulled in through the floor level opening between bell housing and the casing, and is collected in an attached bag or routed to an external dust collection system.
The float bar and/or caster assembly is secured to the back side of the bell housing and configured for height adjustment. The purpose of a float bar assembly, and/or casters in the alternative, is twofold. The primary purpose is to tilt the axis of the sander slightly forward, so that the forward portion of the sanding pad, indicated by the shaded area A, is in contact with the floor. This is necessary in order to maintain positive control of the machine motion and control over its sanding performance. The second purpose is to provide a smooth, sliding contact surface of sufficient surface area to support of the weight of the machine on the back edge of the bell housing without creating or causing an indentation in the floor surface when the weight is being continuously shifted by operator skill between the sanding pad and the float bar assembly, during gliding movement of the machine over the floor surface while sanding.
As is apparent in FIG. 2, which is a top view of the floor level section or bottom of the machine, the rear and in particular the right side of the bell housing has a slightly bulbous extension of its skirt or lower edge, providing somewhat more radial clearance from the disc casing and enclosed sanding disk than on the left side. The intent was to provide a larger cross section area floor level opening for receiving the relatively greater amount of discharge of dust from beneath the sanding pad coming off its forward area of contact with the floor during clockwise rotation.
Dust collection and containment is extremely important to floor edgers and sanders in order to keep floor and wall as clean as possible, avoiding the introduction of that loose particulate matter between the sanding pad and the floor, and increasingly, for improving operator respiratory and vision environmental factors as well.